The present invention relates to a magnetic recording and reproducing apparatus for installing a box-shaped cassette into a video cassette recorder (VCR hereinafter) audio cassette recorder, or the like.
The recent market demands for a VCR integrally combined with a camera are diversified. Not only is reduction in size and weight demanded, but also digitization to prevent deterioration of signals is also demanded. By digitization, the quantity of information is greatly increased as compared with the conventional capacity, and the size of the cassette incorporating a tape is rapidly getting smaller due to the progress in the signal compression technology and high density recording technology. Also, the cassettes possessed by users are increasing year after year, and a VCR system capable of easily retrieving the type of cassette or retrieving the information recorded on the tape is being demanded.
As an example to satisfy such market needs, the household digital VCR (DVC hereinafter) conforming to the DV standard is known. In the DVC, a ferromagnetic metal material is applied or evaporated onto the tape, and the recording density is enhanced by short wavelength recording. A perspective view showing the appearance of a DVC cassette is given in FIG. 22. At the back side of the DVC cassette, an ID board 102a is provided, and by the resistance value of the circuit board read through a contact type recognition switch (MIC-SW hereinafter) mentioned below, the tape thickness, tape material, and other information can be detected.
A conventional magnetic recording and reproducing apparatus is described below while referring to the accompanying drawings.
FIG. 16 is a plan view of a conventional magnetic recording and reproducing apparatus in an unload position, FIG. 17 is a magnified plan view of essential parts of FIG. 16, FIG. 18 is a plan view in a loading completed position, FIG. 19 is a right side view of FIG. 16 in a cassette attaching and detaching position, FIG. 20 is a right side view of FIG. 16 of the cassette in a tape loading position, and FIG. 21 is a right side view of FIG. 18.
In FIG. 16 and FIG. 20, a rotary head cylinder 101 is installed in a main chassis 100, and signals are exchanged with a tape (not shown) incorporated in a cassette 102. A sub-chassis 104 is slidably placed on a sub-chassis guide pin 103 set up in the main chassis 100. As shown in FIG. 19, one end of a main arm 106 rotatably supported on a main arm shaft 105 provided in the sub-chassis 104 is slidably engaged with a main arm pin 108 provided at the side of a cassette holder 107 for conveying the cassette 102.
A a sub-arm shaft 110 is provided at the side of the cassette holder 107 to which an outer panel 109 is attached to the upper part thereof, and a sub-arm 111 is rotatably supported. The leading end of the sub-arm 111 is slidably engaged with a sub-arm pin 112 provided at the side of the sub-chassis 104. The main arm 106 and sub-arm 111 are rotatably engaged with each other about an arm coupling pin 113, and an up-spring 114 is stretched between them, so that the cassette holder 107 is always thrust to move in the direction of arrow A in FIG. 19.
As shown in FIG. 16, FIG. 18, and FIG. 20, a light emitter 115 is disposed at a specified position on the sub-chassis 104, and the light 116 emitted from the light emitter 115 is divided into two directions as indicated by the twin dot chain line, passes through the tape in the cassette 102 and a slot 110a in the sub-arm 111, and reaches a photo detector 117 provided at the side of the sub-chassis 104. Depending on whether or not this light 116 reaches the photo detector 117, the tape starting or ending position can be detected.
Further, a lock rod 119 is slidably provided on a guide pin 118 formed at the side of the sub-chassis 104, and it is thrust in the direction of arrow C in FIG. 19 by a lock spring 120. A lock pin 121 set up on the lock rod 119 is provided at a position to be engaged with a lock engaging portion 107a formed in the cassette holder 107, and the cassette holder 107 is designed to have a slight play after locking so as to be movable somewhat in the direction of arrow B, so that the lock pin 121 can securely contact the stopping portion 107b of the engaging portion 107a. 
In addition, as shown in FIG. 19 or FIG. 20, a contact type recognition switch (MIC-SW) 122 is provided at a position to be engaged with the ID board 102a at the back side of the cassette 102. To insulate all but a contact terminal 122a, the housing 122b for holding the contact terminal 122a is generally made of a resin material. The contact terminal 122a is made of an elastic conductive material, and the resistance value of the ID board 102a can be read by applying a specified pressure.
In this conventional magnetic recording and reproducing apparatus, the operation is described below.
In FIG. 19, when the cassette 102 is put into the cassette holder 107 in the direction of arrow C, and the outer panel 109 is pressed in the direction of arrow B, the cassette holder 107 is lowered as being guided by the main arm 106 and sub-arm 111. When the lock engaging portion 107a of the cassette holder 107 contacts with the lock pin 121, the lock rod 119 slides in the direction of arrow D, and the moment the lock engaging portion 107a passes the lock pin 121, the lock rod 119 returns to the position shown in FIG. 20 due to the thrusting force of the lock spring 120.
After locking the cassette holder 107, when the outer panel 109 is pressed in the direction of arrow B in FIG. 20, the cassette holder 107 is pushed by virtue of the play mentioned above, but when the pushing force is released, it stops at the position shown in FIG. 20 due to the restoring force of the up-spring 114. When the cassette holder 107 descends, the optical path from the light emitter 115 to the photo detector 117 is temporarily shut off by the sub-arm 111, but at the end of descending, the optical path is formed as shown in FIG. 16 and FIG. 20. Thereafter, the sub-chassis 104 mounting the cassette holder 107 is guided by the sub-chassis guide pin 103, and is moved to the rotary head cylinder 101 side, so that the tape can be recorded or reproduced.
The conventional construction; however, has the following three problems.
(1) Since the moving trajectory of the sub-arm intersects with the detection direction of the photo detector, the photo detector must be placed at the outside of the sub-arm, i.e. at the side of the sub-arm that is opposite to the cassette. Therefore, minimizing the width of this mechanism is restricted, and the entire apparatus cannot be reduced much in size.
(2) The MIC-SW is made of a resin material in order to assure its own rigidity and the reliability of operation, and hence a certain thickness is required; however, this thickness becomes a dominant factor for determining the depth of the recognition switch, and hence reducing the depth of the recognition swtich is limited. If an ultra-thin MIC-SW is made, the verticality of the MIC-SW to the chassis is not assured, and fluctuations of contact pressure of the contact terminal with the ID board increase, whereby the reliability of operation of the apparatus becomes inferior.
(3) Since the outer panel and the cassette holder are integrally composed, the external force acting on the outer panel directly propagates to internal mechanisms through the cassette holder. Therefore, in the case of the camera-VCR integrated unit, since the user directly touches the outer panel when operating the unit, the apparatus or the cassette may be distorted or deformed, and the reliability may be spoiled, and hence the quality of the product may be lowered.
The invention is intended to solve these problems of the prior art, and it is hence an object thereof to present a magnetic recording and reproducing apparatus suited to reduction in size and high operation reliability.
To solve the problems of the prior art, the magnetic recording and reproducing apparatus of the invention is characterized by a construction in which the moving trajectory of the sub-arm due to vertical movement of the holder when loading or unloading the cassette does not intersect with the detection direction of the photo detector, and the wall thickness of the cassette judging structure (MIC-SW) is thin. Also, a protecting mechanism for gripping the MIC-SW is provided, and an external force acting on the outer panel is prevented from being applied directly to the cassette holder.
In such construction, the width and/or depth dimension of the apparatus can be reduced, and the cassette and the internal mechanisms are not distorted or deformed due to any external force during operation of the apparatus, so that a highly reliable magnetic recording and reproducing apparatus may be realized.
More specifically, according to a first aspect of the invention, the invention relates to a magnetic recording and reproducing apparatus comprising a chassis, a cassette holder for holding a cassette incorporating a tape, and a moving mechanism composed of a pair of mutually rotatably supported arms. The moving mechanism is for reciprocally moving the cassette holder between a first position for attaching or detaching the cassette to or from the cassette holder, and a second position for placing the cassette in the chassis. The magnetic recording and reproducing apparatus further comprises a detecting mechanism including a detecting member provided adjacent the side of the cassette for detecting the starting or ending position of the tape, and a guide pin provided in the detecting member at the chassis side, such that while the cassette holder is moved reciprocally between the first position and the second position, one of the pair of arms moves at the opposite side of chassis with respect to the detecting member, and the other arm is guided by the guide pin and moves at the chassis side with respect to the detecting member. Therefore, since the pair of arms moves without intersecting with the detection direction of the detecting member, the width of the apparatus can be reduced.
According to a second aspect of the invention, the invention relates to a magnetic recording and reproducing apparatus comprising a chassis, a cassette judging mechanism fixed to the chassis and engageable with the back side of a cassette, for judging the type of the cassette. The apparatus further comprises a protective device provided in the chassis for gripping the cassette judging mechanism.
According to a third aspect of the invention, the protective device is a metal plate member having a pi-shaped protective portion for gripping the upper end of the cassette judging mechanism, and therefore, since the cassette judging mechanism is supported as being fixed by both the chassis and protective device, the depth of the apparatus can be reduced while maintaining the reliability of the cassette judging mechanism.
According to a fourth aspect of the invention, the invention relates to a magnetic recording and reproducing apparatus comprising a main chassis on which a rotary head cylinder is mounted. The apparatus also comprises a cam portion, a sub-chassis reciprocally movable between an unloading position for drawing out a tape from a cassette, and a loading position for recording or reproducing by the rotary head cylinder. A cassette holder is reciprocally movable between an installing position for placing the cassette in the sub-chassis and a cassette attaching/detaching position. A stopping mechanism is engaged with a cam portion of the main chassis. During a released condition of the stopping mechanism, allowed for is reciprocal motion of the cassette holder between the installing position and the cassette attaching/detaching position when the sub-chassis is at the unloading position. And, during a locked condition of the stopping mechanism, allowed for is holding of the cassette holder on the sub-chassis when the sub-chassis is at the loading position.
According to a fifth aspect of the invention, the stopping mechanism is rotatably provided on the sub-chassis, and has one end engaged with the cam portion of the main chassis.
According to a sixth aspect of the invention, the cam portion of the main chassis is composed of a cam face directed in the longitudinal direction parallel to the moving direction of the sub-chassis, and is also composed of a concave face.
In such a construction, when the sub-chassis is at the first position, the stopping mechanism maintains a position for allowing the motion of the cassette holder, and when the sub-chassis is at the second position, the stopping mechanism holds the cassette holder on the sub-chassis, and also clears the engagement between the moving mechanism and the cassette holder. That is, if the user directly touches the outer panel when operating the apparatus, an external force does not propagate to the moving mechanism, and the apparatus or cassette is not distorted or deformed, so that a camera-VCR integrated unit of high reliability and high quality is realized.